HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Chronic passive cigarette smoke exposure augments bronchopulmonary C-fibre inputs to nucleus tractus solitarii neurones and reflex output in young guinea-pigs.

Abstract
1. Children chronically exposed to environmental tobacco smoke (passive cigarette smoke) have more wheeze, cough, bronchoconstriction, airway hyper-reactivity and mucous secretion, which may result, in part, from stimulation of the vagal bronchopulmonary C-fibre reflex. 2. Environmental tobacco smoke increases the sensitivity of bronchopulmonary C-fibre endings, but the physiological relevance of this sensitization is unknown. If this exposure augments the reflex responses via a central mechanism, then the responses of higher-order neurones in the reflex pathway and some components of the reflex output should also be augmented. 3. Guinea-pigs were chronically exposed to sidestream tobacco smoke (surrogate for environmental tobacco smoke) or filtered air for 5 days week-1 from age 1 to 6 weeks (age equivalent of human childhood) and were then anaesthetized, paralysed, ventilated and prepared with pneumothoraces. Baseline and left atrial capsaicin (0.5 and 2.0 microg kg-1)- evoked changes in the impulse activity of vagal C-fibre-activated neurones in nucleus tractus solitarii (NTS), phrenic nerve activity, tracheal pressure, arterial blood pressure and heart rate were compared in the two groups. 4. Sidestream smoke exposure significantly augmented the peak (P = 0.02) and duration (P = 0.01) of the NTS neuronal responses and the prolongation of expiratory time (P = 0.003) at the higher capsaicin dose. 5. Thus, the sensitization of the bronchopulmonary C-fibre endings by chronic exposure to sidestream tobacco smoke is transmitted to the NTS and is associated with a prolonged reflexively evoked expiratory apnoea. The findings may help to explain some related respiratory symptoms in children and be a factor in sudden infant death syndrome.
AuthorsT Mutoh, J P Joad, A C Bonham
JournalThe Journal of physiology (J Physiol) Vol. 523 Pt 1 Pg. 223-33 (Feb 15 2000) ISSN: 0022-3751 [Print] England
PMID10673557 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
Chemical References
  • Tobacco Smoke Pollution
Topics
  • Animals
  • Animals, Newborn (physiology)
  • Bronchi (innervation)
  • Electrophysiology
  • Guinea Pigs
  • Lung (innervation)
  • Male
  • Nerve Fibers (physiology)
  • Neurons (physiology)
  • Reflex (physiology)
  • Solitary Nucleus (cytology, physiology)
  • Time Factors
  • Tobacco Smoke Pollution

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: